Chapter 3

Question 1

What is the purpose of the KR-20 (Kuder-Richardson 20)?

Answer 1

Measures interitem consistency on an exam

Question 2

What is the range for the KR-20? What is an acceptable score?

Answer 2

Ranges from -1.0-1.0
1 = perfect reliability
0 = test lacks reliability
Acceptable score is 0.60

Question 3

The most accurate measure of an item’s level of discrimination is:

Answer 3

The point biserial index (PBI)

Question 4

How does a CNE interpret the PBI?

Answer 4

Ranges from -1.0-1.0
Positive PBI means the item discriminates well, the high scoring students performed better on this item than the lower scoring students
Negative PBI means lower scoring students answered a test item correctly more frequently than higher scoring students

Question 5

What is an acceptable PBI?

Answer 5

0.20 and above

Question 6

According to the PBI, when should an exam item be revised?

Answer 6

When PBI <0.20

Question 7

What is an acceptable range for an item’s p-value (difficulty level)?

Answer 7

0.70-0.80